In this work, SiC nanofiber reinforced SiC (SiCnf/SiC) ceramic matrix composites with 10% (mass fraction) of nanofiber were fabricated by the hot pressing (HP) using SiC nanofiber as reinforcement, which were coated with pyrolysis carbon (PyC) via chemical vapor deposition, SiC powders as matrix and Al2O3-Y2O3 as sintering aids. The effects of deposition time of the PyC coating on density, fracture surface morphology and mechanical properties of SiCnf/SiC ceramic matrix composites were investigated. The results show that PyC layer has a layered graphite structure with good crystallinity, and the coating thickness of PyC prepared by deposition at 1 100 ℃ for 60 min is 10 nm. The fracture toughness of SiCnf/SiC ceramic matrix composites with the SiCnf content of 10% is (19.35±1.17) MPa·m1/2, which is 35% higher than that of composites without PyC coating, with the bending strength of (375.5±8.5) MPa and relative density of 96.68%. In addition, the phenomenon of nanofiber pulling out is observed in the fracture section of the composites. However, the SiCnf/SiC ceramic matrix composites exhibit brittle fracture due to the strong interfacial bond between the nanofiber and matrix and short pull-out length of nanofiber. This work can be used as a reference for the interface design of SiCnf/SiC ceramic matix composites.